Ram-jet mounting structure



Aug. 2, 1960 J. l.. NORTON RAM-'JET MOUNTING STRUCTURE 2 Sheets-Sheet 1 Filed Oct. 23, 1957 ATTGRN E75 J. L. NORTON RAM-JET MOUNTING STRUCTURE Aug. 2, 1960 Filed Oct.A 25, 1957 .Ji No R7: N

ATTckn/EyS United 2,947,140 RAM-JET MOUNTING STRUCTURE IJames Lansdowne Norton, Bristol, England, assignor Vto Bristol Aero-Engines Limited, Bristol, England Filed Oct. 23, 1957, Ser. No. 692,002

Claims. (Cl. 60-35.6)

` This invention relates to ram-jet engines of the kind comprising an outer air casing and an inner island" body arranged within the air casing so that an annular air duct is formed between them in which the enteringv air is Ycompressed by virtue of the forward velocity of the engine.` Such-engines also comprise meansfor injecting fuel into `the Aair tlowing through or leaving the annular duct` and means for maintaining stable com-` of the air casing downstream of the bustion in part island., e Y i y Y i In the interest of lightness and economy the air casing ha'st'o bemade cflight Ygaugel material,l and, unless extensively stifened, is readily distortable under theA improved construction of such engines which substan? tially relieves the air casing of such distortion-causing loads, 'and materially stiffens it in the region of the annular air duct.

According to the invention a ram-jet engine comprises an outer air casing of light distortable construction, an

inner island constructed at least in part as a shapemaintaining rigid body and forming with said outer air casing an annular air duct, a main spar extending from ein* ice

is stitfened and braced by other constructional members. Arranged within the air casing at its forward end is an inner island indicated generally bythe reference numeral 11. The island is coaxially arranged with respect to the air casing so that an annularair duct 12 is formed between them in which the air entering at the intake 13 is compressed by virtue of theforward velocity of the engine. The lrear 'end of the island carries a` llame holder 55 facing downstream into which and around which fuel'is sprayed so that stable combustion can be maintained in the |downstream zone 16. Fuel` is supplied froma fuel tank (not shown) arranged in the vehicle A17 towhich the engine is attached, through a pipe 18, fuel metering apparatus 19 arranged in the vehicle or in a-forward part 20 of the island: 11 and pipes21, 22and 23. The products of combustion are discharged through a convergent-divergent nozzle 24 at' the rear end of the engine, the nozzle which forms a double walled structure with the airv casing 10'at its rear end serving to stilfen the air casing 10,in the region of its rear end.

The central part 25 of-the island 11 is constructed as a -shape-maintaining-n'gid body. In the example being described the central part 25 is composed of two forged or cast 4flanged ring members 26'and 27 interconnected by a lstout wrapper plate 28 welded to the anges vofthe e ring members at 29 and' 30. In the example being dethe'rigid body across the annular air duetto mounting 1 means externally of the air casing, and a plurality of struts extending from the rigid body across the annular air duct to the air casing whereby the latter is braced to the rigid body.

In the preferred construction according to the invention the rigid body is connected to the air casing by a plurality of hollow vanes, all but one of said hollow vanes constituting said struts and the remaining one of said hollow vanes which is preferably of stronger construction than the others, constituting said main spar and being in stress-carrying connection with a portion of the air casing which is of greater stiffness than the remainder of the air casing and is provided with mounting means projecting from its outer surface. The preferred construction of a ram-jet engine according to the invention will now be described in detail, merely by way of example with reference to the drawings accompanying the provisional specification whereof Figure l is a side elevation` of the engine,p`artly inz section; v

Figures 2 and 3 are transverse sections taken respectively along the lines 2.-2 and 3;-3 in Figure l; and

Figure 4 is a longitudinal section taken along the line 44, in Figure l.

The ram-jet engine illustrated in the drawingscomprises a substantially cylindrical outer air casing 10 which is constructed'mainly of light gauge sheetmetal and is therefore fairly easily distortable except in so far as it scribed the forward part 20 of the island 11 is also a ngid cast body bolted tothe forward ilanged ring'26. Extending from the rigid body 25 across the annular: air

duct 12 is a main spar 31. The spar 31 comprises a' .box-like structure composed of two side members 32 and 33 extending inthe direction of air flow through the annular air duct and two anged end members 34 andY Amember 37-has onits outer surface projecting ilanges 38 constituting mounting means by which the engine is at-l tached to a iin structure 39 projecting froma vehicle,A

17. It will thus be appreciated that the island 11 is rigidly supported from the vehicle 17 by the spar 31 but that the air casing 10, apart from the portion constituted by the member 37, is still relatively distortable. To overcome this undesirable ilexibility, two further struts, comprising U-sectioned members 40, are attached to the central part 25 of the island and extend across the annular air duct 12 to the air casing 10 so as to brace the air casing to the inner island.

The spar 31 and the U-shaped members 40 are provided at their forward `ends with hollow nose portions 41 which taper in the upstream direction of air flow through the annular air duct, the portions terminating in knife edges in the region of the intake opening 13 of the annular air iduct. These tapering portions are formed integrally with the forward part 20 of the island, and as shownin Figure 4, the tapering portion 41 pertaining tothe spar structure is bolted to the box-like structure referred to above; as at 57, and s provided with a conduit 42 through whichV the fuel pipe 13 passes from the vehicle to the fuel meteringapparatus 19'. The tapering portions 41 pertaining to the U-shaped members 40 are likewise bolted to them as at 57 in Figure 2. At their rear Vends Athe spar 31 and the U-shaped members 40 are also provided with portions 43 tapering in the downstream direction of air ow through the annular air duct.V The portions 43 are of sheet metal construction and. taper to knife edges. The spar and-the struts--as described are, it will be appreciated, in the form of hollow vanes connecting the rigid part of the island 11 to the. outerY air casing l so as` to brace the air casing, the vane. which constitutes the maiuspar supporting the island 11 from'the vehicle and being of stronger construcf tion than the other vanes.

At, its. rear end the engine is attached yto lthe vehicle;v 17 by a joint or joints whichallows the lair casing-10 to expand in the longitudinalv direction Without restraint butv which supports the rear endof the casing lto relieve themain spar connection 3S of torsional stresses.

As. Ashown in the drawing this connection comprises pins 44 extending in the axiale direction of the engine and forming a'connection between spaced ntercalated lugs :45 :carried vby the air casing and 'x'ed arms 46 attachedto the vehicle 17, the arrangementvresembling hinges withendwise freedom of movement betweenthe two parts. It will be noted that this connection'is attached toA the airV casing vat* a region where the air casing is protected from the exhaust a'megand therefore not weakened by high tempera-tures, and is stiiiened` in a shape-maintaining mannerV byv the discharge nozzle 24.

I claim: l. A ram-jet engine comprising an outer-aiocasing of light distortable construction, an inner island con-A structed at-leastin part as a shape-maintaining rigid body nular VairV duct to the air casing whereby the latter is* bracedY to the rigid body.

2: Aram-jet engine as claimed in` claim? 1l; wherein said struts and said Ymain spar are each in the form -ofs a hollow vanerand the vane constituting saidmain spar is `in stressl carrying connection with a portion of the airY casing-.which is of 'greater stiffness than the remainder of the air casingysaid portion of the air casing carrying said mounting meansV projecting from its outersurface. 3. A ram-jet engine as claimed in claiml 2, wherein aicentral part of the inner island is constructed as a shape maintaining rigid body.

4.'A. ram-jet engine as claimed in claim 3, wherein the centralY part of the inner island is composed 'of twor flanged ring members interconnected by a plate member welded to theflanges-of the ring members.

5. Aram-jet-engine -as'claimed in claim 3 wherein said main spar comprises a box-like structure composed of two side members extending in the direction of air flow through the annular air duct and two end members extending transversely of the direction of air flow through the annular air duct, said side and end members being connected together to form said box-like structure and said side and end members extending between and being connected to said stiiener portion of said air casing and said innerisland.

6. Aram-jet engine as claimed'in claim 3, wherein each of said struts comprises an intermediate' U-sectioned member extending betweenand being connected to said central part of the inner island and to said outer air casing,`a nose portion tapering upstream in said annular air duct to a knife edge in the region of the intake end of said annular air duct, said nose portion being formed integrally with the part of the inner island forward 'of said "central part; and a trailing portion of sheet metal. construction tapering downstream in said annular-air' 7. A ram-jet engine as claimed in claim 5, wherein. sa-id main spar further; comprises, at its forward end,'a. nose portion tapering upstream in said annular air duct to afknife` edge in ythe region of the intake end of said annular air duct, said tapering nose portion being formed.

integrally with the part of the inner island forward of said centralv part,` and, atits rear end, a trailing portion.

ofsheet metal construction, tapering downstream in said` annular air duct;

8.`A ram-jet engine as claimedin claim 3, wherein.

the part ofthe inner island forward of the centraljpart is Valso constructed as a shape vmaintaining rigid tbody.v

9..A ram-jet engine as, claimed in claim 1 wherein.,

No references cited.v 

